feat: implement net.cidr_expand builtin

[Tyler Schade (tjons)]

Implements net.cidr_expand from #96.

Anand Krishnamoorthi (@anakrish) the rvm implementation seems to have caused some issues with clippy checking lifetimes during precommit hooks:

123 - impl<'a> Serialize for BinarySetRef<'a> {
123 + impl Serialize for BinarySetRef<'_> {
    |

error: the following explicit lifetimes could be elided: 'a
   --> src/rvm/program/serialization/value.rs:138:6
    |
138 | impl<'a> Serialize for BinaryObjectRef<'a> {
    |      ^^                                ^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
help: elide the lifetimes
    |
138 - impl<'a> Serialize for BinaryObjectRef<'a> {
138 + impl Serialize for BinaryObjectRef<'_> {
    |

error: the following explicit lifetimes could be elided: 'a
   --> src/rvm/program/serialization/value.rs:153:6
    |
153 | impl<'a> Serialize for BinaryEntryRef<'a> {
    |      ^^                               ^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
help: elide the lifetimes
    |
153 - impl<'a> Serialize for BinaryEntryRef<'a> {
153 + impl Serialize for BinaryEntryRef<'_> {
    |

error: could not compile `regorus` (lib) due to 19 previous errors
warning: build failed, waiting for other jobs to finish...
error: could not compile `regorus` (lib test) due to 19 previous errors
error: failed to push some refs to 'github.com:tjons/regorus.git'

is this expected?

[Anand Krishnamoorthi (anakrish)]

Tyler Schade (@tjons) I haven't seen those errors. Let me check.

[Anand Krishnamoorthi (anakrish)]

Hey Tyler Schade (@tjons), I am not able to reproduce those clippy errors. Which toolchain are you on?

[Tyler Schade (tjons)]

Anand Krishnamoorthi (@anakrish) those were on 1.86.0-aarch64-unknown-linux-gnu. I upgraded to 1.89.0-aarch64-unknown-linux-gnu and they resolved, albeit with some new errors related to no_std and the thumbv7m-none-eabi target... I'm unsure what the cause is but I've managed to run the rest of the checks locally manually and this is now ready for review!

[Anand Krishnamoorthi (anakrish)]

LGTM. Thanks, Tyler Schade (@tjons)